The rule is designed to protect “downwind” states from pollution that is generated elsewhere – but then drifts across state borders.

“This rule provides extremely important clean air protections for children, families and communities across the eastern half of the United States,” said David Lifland, Legal Fellow for Environmental Defense Fund (EDF), which intervened in support of the rule. “The pollution reductions at stake today will save lives, and will protect Americans from asthma attacks, heart attacks and other serious health problems.”

EPA issued the Cross-State Air Pollution Rule under the “Good Neighbor” provision of the Clean Air Act, which prohibits emissions from state power plants that contribute significantly to harmful pollution levels in neighboring states. The rule reduces the sulfur dioxide and oxides of nitrogen pollution emitted from coal-fired power plants across 28 eastern states. That pollution drifts across the borders of those states, contributing to dangerous — and sometimes lethal — levels of particulate and smog pollution in downwind states.

The Cross-State Air Pollution Rule was adopted on July 6, 2011, and compliance with the rule was scheduled to begin January 1, 2012 – but several large power companies and some states, including Texas, sued to stop it. On December 30th, the court agreed to temporarily stay the rule pending further judicial review, and also called for an accelerated hearing schedule. (The same court similarly halted EPA’s first interstate air pollution protection program, and then later affirmed EPA’s action after a complete review of the facts and law).

EDF — together with the American Lung Association, the Clean Air Council, NRDC and Sierra Club — intervened in the case and submitted a brief in support of EPA. Nine states (Connecticut, Delaware, Illinois, Massachusetts, Maryland, New York, North Carolina, Rhode Island, and Vermont), the District of Columbia, and five major cities (Baltimore, Bridgeport, Chicago, New York and Philadelphia) also intervened in support of EPA; they filed a brief emphasizing the importance of the rule for public health and Clean Air Act compliance in downwind jurisdictions. Several major power companies (Calpine, Exelon and Public Service Enterprise Group) also intervened in defense of the Cross-State Air Pollution Rule.

This morning, Judges Rogers, Griffith, and Kavanaugh will hear oral arguments in the case. Each of the three sets of intervenor groups supporting EPA will present oral arguments. Sean H. Donahue, counsel for EDF, will present arguments for the public health and environmental intervenors.

The Cross-State Air Pollution Rule would reduce power plant sulfur dioxide emissions by 73 percent and oxides of nitrogen by 54 percent from 2005 levels. These emissions and the resulting particulate pollution and ozone (more commonly known as soot and smog) impair air quality and harm public health — both near the plants and hundreds of miles downwind. While no one is immune to these impacts, children and the elderly are especially vulnerable.

EPA estimates that the Cross-State Air Pollution Rule, when fully implemented, will:

Save up to 34,000 lives each year

Prevent 15,000 heart attacks each year

Prevent 400,000 asthma attacks each year

Provide $120 billion to $280 billion in health benefits for the nation each year